JP5942874B2 - battery - Google Patents

Description

  The present invention relates to a battery including an electrode body in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are overlapped with each other via a strip-shaped separator and wound in a flat shape around an axis, and a battery case housing the electrode body.

  2. Description of the Related Art Conventionally, a battery including an electrode body in which a strip-like positive electrode plate and a strip-like negative electrode plate are overlapped with each other via a strip-shaped separator and wound flatly around an axis, and a battery case that accommodates the electrode body is known. ing. Further, in such a battery, a flat spacer (a gap in Patent Document 1) that overlaps a flat portion of the electrode body (a portion where the positive electrode plate, the negative electrode plate, and the separator overlap in a flat plate shape) between the battery case and the electrode body. (Refer to FIG. 3 etc. of patent document 1).

JP 2009-048966 A

  By the way, when the positive electrode plate is cut along its longitudinal direction, burrs due to the cutting are likely to remain on the positive electrode cutting edge (cut surface) generated at that time. Similarly, when the negative electrode plate is cut along its longitudinal direction, burrs due to the cutting are likely to remain on the negative electrode cutting edge (cut surface) generated at that time. For this reason, it has been found that when the flat plate portion of the electrode body is pressed with a spacer interposed between the battery case and the electrode body, a short circuit may occur. That is, when the positive electrode cutting edge (or negative electrode cutting edge) is pressed with a spacer, the burr existing on the positive electrode cutting edge (or negative electrode cutting edge) penetrates the separator and is adjacent to the negative electrode plate (or positive electrode plate). This is thought to be caused by a short circuit caused by contact.

  The present invention has been made in view of the current situation, and in a battery in which a spacer is interposed between a battery case and an electrode body, it is appropriate that a short circuit occurs due to the pressing of the electrode body by the spacer. It aims at providing the battery which can be suppressed.

One aspect of the present invention for solving the above problem is that a belt-like positive electrode plate and a belt-like negative electrode plate are wound around each other through a belt-like separator in a flat shape around the axis, An edge portion on one side in the axial direction along the axis is projected in a flat spiral shape from the separator toward the one side, and an edge portion on the other side in the axial direction of the negative electrode plate from the separator. An electrode body projecting in a flat spiral shape toward the other side, a battery case containing the electrode body, and disposed between the battery case and the electrode body, and at least the positive electrode of the electrode bodies And a plate-like spacer that overlaps a flat plate portion in which the negative electrode plate and the separator overlap in a flat plate shape, and the positive electrode plate cuts the positive electrode plate in the longitudinal direction on the other side. Formed Has a positive cutting edge that occurred, the negative electrode plate, to the one side, has a negative cutting edge produced when formed by cutting the negative electrode plate in a longitudinal direction, said spacer, It is made of resin, and among the spacer edges, one side spacer edge located on the one side is 4.0 to 8.0 mm from the negative electrode cutting edge and located on the other side, and the other side The other side spacer edge located in the battery is 4.0 to 8.0 mm from the positive electrode cutting edge, and is arranged in a form located on the one side.

In this battery, while the spacer is arranged so as to overlap the flat plate portion of the electrode body, the one side spacer edge is located on the other side in the axial direction from the negative electrode cutting edge, and the other side spacer edge is positive electrode cut. It arrange | positions in the form located in the one side of an axial direction rather than an edge. For this reason, the positive electrode cutting edge and the negative electrode cutting edge are hardly pressed by the spacer. Therefore, even if burrs are generated at the positive electrode cutting edge or the negative electrode cutting edge, it is possible to appropriately suppress the occurrence of a short circuit in which the burr penetrates the separator and contacts the adjacent positive electrode plate or negative electrode plate by pressing the spacer. it can.
Furthermore, in this battery, the spacer edge on one side of the spacer is arranged on the other side in the axial direction by 4.0 mm or more from the negative electrode cutting edge of the flat plate portion of the electrode body. Further, the other-side spacer edge is arranged on the one side in the axial direction by 4.0 mm or more from the positive electrode cutting edge. In the following, these distances are also referred to as “down distances”. Thereby, since the positive electrode cutting edge and the negative electrode cutting edge are hardly pressed by the spacer, it is possible to more reliably prevent a short circuit due to the pressing of the spacer.
On the other hand, if the pulling distance from the negative electrode cutting edge of the one side spacer edge and the pulling distance from the positive electrode cutting edge of the other side spacer edge are too large, load unevenness occurs in the flat plate portion of the electrode body, It has been found that the capacity deterioration (decrease in capacity retention rate) accompanying the use (charging / discharging) of the battery becomes large. On the other hand, in this battery, the distance of the one side spacer edge from the negative electrode cutting edge is within 8.0 mm, and the distance of the other side spacer edge from the positive electrode cutting edge is within 8.0 mm. It is said. Thereby, capacity degradation accompanying use of a battery can be controlled appropriately.
The “spacer” may be made of an insulating resin or a conductive resin . The “spacer” may be composed of a single layer or a plurality of layers. Further, the “spacer” may be disposed only on one side in the thickness direction of the electrode body, or may be disposed on both sides in the thickness direction of the electrode body. Further, the thickness of the “spacer” may be changed for each battery in consideration of the thickness variation of the electrode body.

It is a perspective view of the battery which concerns on embodiment. It is sectional drawing which follows the battery horizontal direction and battery vertical direction of the battery which concerns on embodiment. It is sectional drawing which follows the battery thickness direction and battery vertical direction of the battery which concerns on embodiment. It is an exploded perspective view of a cover member, a positive electrode terminal member, a negative electrode terminal member, etc. concerning an embodiment. 1 is a perspective view of an electrode body according to an embodiment. It is explanatory drawing which concerns on embodiment and shows the state which the electrode body expand | deployed and the positional relationship with a spacer. It is a graph which shows the relationship between the pulling-down distance of the one side spacer edge and the other side spacer edge, the number of batteries that have short-circuited in the short-circuit test, and the capacity retention rate after the charge / discharge cycle test.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a battery 10 according to the present embodiment. FIG. 4 shows the lid member 23, the positive terminal member 60, the negative terminal member 70, and the like of the battery case 20. Moreover, the electrode body 30 is shown in FIG.5 and FIG.6. Hereinafter, the battery thickness direction BH, the battery horizontal direction CH, and the battery vertical direction DH of the battery 10 will be described as the directions shown in FIGS. The axial direction EH, the electrode body thickness direction FH, and the electrode body width direction GH of the electrode body 30 will be described as the directions shown in FIGS. 2, 3, 5, and 6. In FIG. 3, the description of the positive electrode terminal member 60 and the like is omitted.

The battery 10 is a rectangular sealed lithium ion secondary battery mounted on a vehicle such as a hybrid vehicle or an electric vehicle. The battery 10 is used as an assembled battery in which a plurality of batteries 10 are arranged in the battery thickness direction BH (electrode body thickness direction FH) and restrained while being pressed in the battery thickness direction BH by a restraining member.
The battery 10 includes a rectangular battery case 20, a flat wound electrode body 30 accommodated in the battery case 20, a positive terminal member 60 and a negative terminal member 70 supported by the battery case 20, and the like. It is composed of A non-aqueous electrolyte solution 27 is held in the battery case 20. In the battery 10, a plurality of plate-like spacers 80 are disposed between the battery case 20 and the electrode body 30.

  Among these, the battery case 20 is made of metal (specifically, aluminum). The battery case 20 includes a bottomed rectangular tube-shaped case body 21 having a rectangular opening 21h only on the upper side, and a rectangular plate-shaped lid member 23 that seals the opening 21h of the case body 21. (See FIGS. 1 to 3). In the lid member 23, a non-returnable safety valve 23v is provided near the center in the longitudinal direction (battery lateral direction CH). In addition, a liquid injection hole 23 h that is used when injecting the electrolyte solution 27 into the battery case 20 is provided in the vicinity of the safety valve 23 v and is hermetically sealed by the sealing member 25.

  Further, in the lid member 23, a positive electrode terminal member 60 and a negative electrode terminal member 70 that are extended from the inside of the battery case 20 to the outside are fixed in the vicinity of both ends in the longitudinal direction (FIG. 1, FIG. 1). 2 and 4). Specifically, each of the positive electrode terminal member 60 and the negative electrode terminal member 70 is connected to the electrode body 30 in the battery case 20, and passes through the lid member 23 and extends to the outside of the battery case 20. It is comprised from the member 61,71 and the crank-shaped 2nd terminal member 62,72 which is arrange | positioned on the cover member 23, and was fixed by crimping to the 1st terminal member 61,71. The positive electrode terminal member 60 and the negative electrode terminal member 70 are disposed inside the lid member 23 (inside the case) together with metal fastening members 65 and 75 for fastening connection terminals outside the battery, such as bus bars and crimp terminals. The first insulating members 67 and 77 made of resin and the second insulating members 68 and 78 made of resin disposed outside the case 23 (outside the case) are fixed to the cover member 23.

  Next, the electrode body 30 will be described (see FIGS. 2, 3, 5, and 6). The electrode body 30 is housed in the battery case 20 in a state of being laid down so that the axial direction EH thereof coincides with the battery lateral direction CH (see FIG. 2). The electrode body 30 is formed by laminating a strip-like positive electrode plate 31 and a strip-like negative electrode plate 41 through a pair of separators 51, 51 made of a porous resin and wound around an axis AX to form a flat shape. (See FIGS. 5 and 6).

  The positive electrode plate 31 has a strip-shaped positive electrode foil 32 made of aluminum as a core material. Of the front and back surfaces of the positive electrode foil 32, a part of the width direction (the vertical direction in FIG. 6, the axial direction EH along the axis AX in the state where the electrode body 30 is configured) (the lower portion in FIG. 6, the axial direction) On the other side ED portion of EH, porous positive electrode active material layers 33 and 33 extending in a strip shape in the longitudinal direction MH (left and right direction in FIG. 6) are formed. The positive electrode active material layer 33 is formed of a positive electrode active material, a conductive material, and a binder. In this embodiment, lithium-cobalt-nickel-manganese composite oxide is used as the positive electrode active material, acetylene black (AB) is used as the conductive material, and polyvinylidene fluoride (PVDF) is used as the binder.

  The positive electrode edge 31f of the positive electrode plate 31 has a first positive electrode cutting edge 31fc and a second positive electrode cutting edge 31fd along the longitudinal direction MH, respectively (see FIGS. 2, 5, and 6). The one-side positive electrode cutting edge 31fc is an edge located on the one-side EC in the axial direction EH in the state where the electrode body 30 is configured. Further, the other-side positive electrode cutting edge 31fd is an edge located on the other side ED in the axial direction EH in the state in which the electrode body 30 is configured, and the positive electrode foil 32 and the positive electrode active material layer 33 are arranged along the longitudinal direction MH. This is a cut edge generated when the positive electrode plate 31 is formed by cutting with a slitter. A burr due to the cutting may remain on the other positive electrode cutting edge 31fd.

  The negative electrode plate 41 has a strip-shaped negative electrode foil 42 made of copper as a core material. A part (upper part in FIG. 6, one side of the axial direction EH) of the negative electrode foil 42 in the width direction (up and down direction in FIG. 6, the axial direction EH in the state in which the electrode body 30 is configured). On the EC portion, porous negative electrode active material layers 43, 43 extending in a strip shape in the longitudinal direction NH (left-right direction in FIG. 6) are formed. The negative electrode active material layer 43 is formed of a negative electrode active material, a binder, and a thickener. In this embodiment, natural graphite is used as the negative electrode active material, styrene butadiene rubber (SBR) is used as the binder, and carboxymethyl cellulose (CMC) is used as the thickener.

  The negative electrode edge 41f of the negative electrode plate 41 has a first negative electrode cutting edge 41fc and a second negative electrode cutting edge 41fd along the longitudinal direction NH, respectively (see FIGS. 2, 5, and 6). The one-side negative electrode cutting edge 41fc is an edge located on the one-side EC in the axial direction EH in the state in which the electrode body 30 is configured, and slitters the negative electrode foil 42 and the negative electrode active material layer 43 along the longitudinal direction NH. This is a cut edge generated when the negative electrode plate 41 is formed by cutting at. The one-side negative electrode cutting edge 41fc may leave burrs due to the cutting. The other-side negative electrode cutting edge 41fd is an edge located on the other-side ED in the axial direction EH in the state where the electrode body 30 is configured.

Of the positive electrode plate 31, an end edge portion 31 c on one side EC (in FIG. 2, left side, in FIGS. 5 and 6, upward) in the axial direction EH along the axis AX is directed from the separator 51 toward the one side EC. It protrudes in a flat spiral shape to form a positive electrode protruding wound portion 30 c of the electrode body 30. The first terminal member 61 of the positive electrode terminal member 60 is connected (welded) to the positive electrode protruding winding portion 30c.
Further, in the negative electrode plate 41, an end edge portion 41d on the other side ED in the axial direction EH (right side in FIG. 2, lower side in FIGS. 5 and 6) is a flat spiral from the separator 51 toward the other side ED. The electrode body 30 protrudes in a shape to form a negative electrode protrusion wound portion 30d. The first terminal member 71 of the negative electrode terminal member 70 is connected (welded) to the negative electrode winding portion 30d.

  Of the electrode body 30, a position where the positive electrode plate 31, the negative electrode plate 41, and the separator 51 overlap each other is located inside (center) in the axial direction EH than the positive electrode protruding winding portion 30 c and the negative electrode protruding winding portion 30 d, It is set as the center winding part 30e (refer FIG.2, FIG.3, FIG.5 and FIG. 6). The central winding portion 30e is divided into one curved end portion 30f, the other curved end portion 30g, and a flat plate portion 30h when viewed in the electrode body width direction GH.

  Among these, the one-side curved end 30f is located on one side GA (upward in FIGS. 2 and 3) in the electrode body width direction GH, and the positive electrode plate 31, the negative electrode plate 41, and the separator 51 are bent into a semi-cylindrical shape. It is a part that overlaps each other. The other side curved end 30g is located on the other side GB (upward in FIGS. 2 and 3) in the electrode body width direction GH, and the positive electrode plate 31, the negative electrode plate 41, and the separator 51 are bent into a semi-cylindrical shape. It is a part that overlaps each other. The flat plate portion 30h is located between the one-side curved end portion 30f and the other-side curved end portion 30g, and the positive electrode plate 31, the negative electrode plate 41, and the separator 51 overlap each other in a flat plate shape in the electrode body thickness direction FH. It is.

  Next, the spacer 80 will be described (see FIGS. 2, 3 and 6). The spacers 80 overlap with the flat plate portion 30h of the electrode body 30, and each three spacers 80 are provided between the battery case 20 and the electrode body 30, specifically on both sides of the electrode body 30 in the electrode body thickness direction FH. (6 sheets in total) are arranged. Each spacer 80 has a rectangular plate shape made of polypropylene (PP) having a thickness of 0.10 mm. The long side dimension is smaller than the dimension in the axial direction EH of the flat plate portion 30 h, and the short side dimension is the electrode body 30. It is made larger than the dimension of the electrode body width direction GH.

  Specifically, the spacer 80 has four spacer edges 80f. Among these, in the state where the battery 10 is configured, an edge that is located on one side EC of the spacer 80 and is disposed along the electrode body width direction GH is referred to as a one-side spacer edge 80fc. The one-side spacer edge 80fc is disposed on the other side ED in the axial direction EH of 4.0 to 8.0 mm from the one-side negative electrode cutting edge 41fc of the negative electrode plate 41 in the flat plate portion 30h of the electrode body 30. (See FIGS. 2 and 6). In the present embodiment, the pull-down distance Lc is Lc = 4.0 mm.

  In addition, an edge located on the other side ED of the spacer 80 and disposed along the electrode body width direction GH is referred to as an other-side spacer edge 80fd. The other-side spacer edge 80fd is arranged on the one-side EC in the axial direction EH of 4.0 to 8.0 mm from the other-side positive electrode cutting edge 31fd of the positive electrode plate 31 in the flat plate portion 30h of the electrode body 30. (See FIGS. 2 and 6). In the present embodiment, the pull-down distance Ld is Ld = 4.0 mm.

In addition, an edge disposed along the axial direction EH of the electrode body 30 on one side GA in the electrode body width direction GH is defined as a width direction first edge 80fe. The first edge 80fe in the width direction is further disposed on the one side GA in the electrode body width direction GH than the one side curved end 30f of the electrode body 30 (see FIGS. 2 and 3).
In addition, an edge disposed along the axial direction EH of the electrode body 30 on the other side GB in the electrode body width direction GH is defined as a second edge 80ff in the width direction. The second edge 80ff in the width direction is further disposed on the other side GB in the electrode body width direction GH than the other side curved end 30g of the electrode body 30 (see FIGS. 2 and 3).

Next, a method for manufacturing the battery 10 will be described. A positive electrode plate 31, a negative electrode plate 41, and separators 51, 51 are prepared, and the positive electrode plate 31 and the negative electrode plate 41 are overlapped with each other via the separators 51, 51 (see FIG. 6), and around the axis AX using a winding core. Turn around. Further, this is compressed into a flat shape to form the electrode body 30 (see FIG. 5).
Separately, the lid member 23, the first terminal members 61 and 71, the second terminal members 62 and 72, the fastening members 65 and 75, the first insulating members 67 and 77, and the second insulating members 68 and 78, Prepare each. And using these, the positive electrode terminal member 60 and the negative electrode terminal member 70 are respectively fixed to the lid member 23 (see FIG. 4). Thereafter, the positive electrode terminal member 60 and the negative electrode terminal member 70 are welded to the electrode body 30.

  Next, six spacers 80 are prepared, and three of these spacers 80 are stacked on both sides of the flat plate portion 30 h of the electrode body 30. At that time, each one-side spacer edge 80fc is located on the other side ED in the axial direction EH of Lc = 4.0 mm from the one-side negative electrode cutting edge 41fc of the flat plate portion 30h, and each other-side spacer edge The spacer 80 is arranged in a form in which 80 fd is located on one side EC in the axial direction EH of Ld = 4.0 mm from the other-side positive electrode cutting edge 31 fd of the flat plate portion 30 h.

  Next, the case main body 21 is prepared, and after the electrode body 30 and the spacer 80 are accommodated in the case main body 21, the case main body 21 and the lid member 23 are welded to form the battery case 20 (FIGS. 1 to 3). reference). Thereafter, the electrolytic solution 27 is injected into the battery case 20 from the injection hole 23h, and the injection hole 23h is hermetically sealed with the sealing member 25. Thereafter, the battery is subjected to initial charging and various inspections. Thus, the battery 10 is completed.

(Test results)
Next, the results of tests performed to verify the effects of the battery 10 according to the embodiment will be described. In the battery 10 according to the embodiment, the reduction distances Lc and Ld of the one-side spacer edge 80fc and the other-side spacer edge 80fd from the one-side negative electrode cutting edge 41fc or the other-side positive electrode cutting edge 31fd are set to −2.0. Ten types of batteries were manufactured by changing the distance to ˜16.0 mm at intervals of 2.0 mm. In manufacturing these batteries, a burr having a height of 60 μm was formed on each of the one-side negative electrode cutting edge 41fc and the other-side positive electrode cutting edge 31fd in the flat plate portion of the electrode body using a nipper.

Ten batteries were prepared and a “short circuit test” was performed. Specifically, each battery was sandwiched between a pair of restraining plates from both sides in the battery thickness direction BH (electrode body thickness direction FH) and restrained while being pressed at 5 kN (2600 kPa).
Thereafter, it was inspected whether or not a short circuit occurred in the electrode body 30 from the voltage change in the self-discharge process. Specifically, (1) The battery voltage is measured at 20 ° C. (2) Five days later, the battery voltage is measured again. (3) Then, the median of the voltage change for 5 days was obtained for 10 batteries, and the battery that had decreased from this median by −0.33 mV / 5 days or more was judged as a battery in which a short circuit occurred. The result is shown in FIG.

As can be seen from the graph of FIG. 7, in the battery in which the pull-down distances Lc and Ld of the one side spacer edge and the other side spacer edge are Lc = Ld = −2.0 mm, 5 out of 10 batteries are short-circuited. In addition, in the battery with Lc = Ld = 0.0 mm, a short circuit occurred in four out of ten batteries.
On the other hand, in a battery with Lc = Ld = 2.0 mm, a short circuit occurs only in three of the ten batteries, a battery with Lc = Ld = −2.0 mm, and Lc = Ld = 0. Short-circuiting is less likely to occur than with a 0 mm battery. Furthermore, in each battery with Lc = Ld = 4.0 to 16.0 mm, none was short-circuited.

  The reason is considered as follows. That is, when the battery is restrained while being pressed by the restraining plate, the spacer interposed between the battery case 20 and the electrode body 30 presses the flat plate portion 30 h of the electrode body 30. Then, in the battery with Lc = Ld = −2.0 mm, or the battery with Lc = Ld = −0.0 mm, the other-side positive electrode cutting edge 31 fd and the one-side negative electrode cutting edge 41 fc are particularly strongly pressed by the spacer. Is done. For this reason, in many batteries, the burrs present on the other-side positive electrode cut end edge 31fd or the one-side negative electrode cut end edge 41fc contact the adjacent negative electrode plate 41 or the positive electrode plate 31 through the separator 51 to cause a short circuit. It is thought.

  On the other hand, in the battery with Lc = Ld = 2.0 mm, the one side spacer edge and the other side spacer edge are 2.0 mm inside than the other side positive electrode cutting edge 31 fd and the one side negative electrode cutting edge 41 fc, respectively. Therefore, as the battery with Lc = Ld = −2.0 mm and the battery with Lc = Ld = −0.0 mm, the other-side positive electrode cutting edge 31 fd and the one-side negative electrode cutting edge are separated by the spacer. 41fc is not pressed strongly. For this reason, it is considered that the burr of the other-side positive electrode cutting edge 31fd or the one-side negative electrode cutting edge 41fc penetrates the separator 51 and contacts the adjacent negative electrode plate 41 or positive electrode plate 31 to suppress a short circuit. .

  Furthermore, in each battery with Lc = Ld = 4.0 to 16.0 mm, the one side spacer edge and the other side spacer edge are larger than the other side positive electrode cutting edge 31fd and the one side negative electrode cutting edge 41fc, respectively. Since it is located inside (4.0 mm or more), the other-side positive electrode cutting edge 31fd and the one-side negative electrode cutting edge 41fc are hardly pressed by the spacer. For this reason, it is considered that the burr of the other-side positive electrode cutting edge 31fd or the one-side negative electrode cutting edge 41fc is prevented from coming into contact with the adjacent negative electrode plate 41 or positive electrode plate 31 through the separator 51 and causing a short circuit. .

  Next, for each of the 10 types of batteries described above, a “charge / discharge cycle test” was performed using the batteries that were restrained by the restraint plate as described above and did not cause a short circuit, and the capacity retention rate was determined. Specifically, each battery was charged from 3.57V (SOC 30%) to 3.88V (SOC 80%) at a constant current of 2C and then 3.88V at a constant current of 2C at an environmental temperature of 60 ° C. Charging / discharging to discharge from (SOC 80%) to 3.57 V (SOC 30%) was taken as one cycle, and this was performed 1000 cycles. And about each battery, the ratio of the battery capacity after the charging / discharging test with respect to the battery capacity before the charging / discharging cycle test was calculated | required, and this was made into the capacity | capacitance maintenance factor. The result is shown in FIG.

As can be seen from the graph of FIG. 7, in the battery with Lc = Ld = 14.0 mm, the capacity retention rate after the charge / discharge cycle test is low (about 86%), and in the battery with Lc = Ld = 16.0 mm, The capacity retention rate was even lower (about 78%).
On the other hand, in each battery in which the pull-down distances Lc, Ld of the one side spacer edge and the other side spacer edge are Lc = Ld = −2.0 to 12.0 mm, The capacity maintenance rate was high (over 92%).

The reason is considered as follows. That is, in the battery in which Lc = Ld = 14.0 mm and the battery in which Lc = Ld = 16.0 mm, the pull-down distances Lc and Ld are too large, so that the spacer is not pressed by the spacer in the flat plate portion 30h of the electrode body 30. The number of portions increased, and load unevenness occurred in the flat plate portion 30 h of the electrode body 30. As a result, it is considered that the capacity maintenance rate has decreased.
On the other hand, in each battery with Lc = Ld = −2.0 to 12.0 mm, there are few portions of the flat plate portion 30h of the electrode body 30 that are not pressed by the spacer, and the flat plate portion 30h of the electrode body 30 has load unevenness. Not likely to occur. For this reason, it is considered that the capacity maintenance rate has increased.

  As described above, in the battery 10, the spacer 80 is arranged so as to overlap the flat plate portion 30 h of the electrode body 30, but the one side spacer edge 80 fc is more than the one side negative electrode cut edge 41 fc of the negative electrode plate 41. The second spacer end edge 80fd is positioned on the other side ED in the axial direction EH, and is positioned on the first side EC in the axial direction EH with respect to the other positive electrode cutting end edge 31fd of the positive electrode plate 31. For this reason, the other side positive electrode cutting end edge 31 fd and the one side negative electrode cutting end edge 41 fc are hardly pressed by the spacer 80. Therefore, even if burrs are generated in the other-side positive electrode cutting edge 31fd and the one-side negative electrode cutting edge 41fc, the burrs penetrate the separator 51 by the pressing of the spacer 80 and are adjacent to the adjacent positive electrode plate 31 or negative electrode plate 41. It can suppress appropriately that the short circuit which contacts is produced.

  Furthermore, in the present embodiment, one side spacer edge 80fc of the spacer 80 is disposed on the other side ED in the axial direction EH by 4.0 mm or more than the one side negative electrode cutting edge 41fc of the flat plate portion 30h of the electrode body 30. Yes. Further, the other-side spacer end edge 80fd is arranged on the one-side EC in the axial direction EH by 4 mm or more than the other-side positive electrode cutting end edge 31fd. Thereby, the other-side positive electrode cutting end edge 31fd and the one-side negative electrode cutting end edge 41fc are hardly pressed by the spacer 80, so that a short circuit due to the pressing of the spacer 80 can be prevented more reliably.

  On the other hand, if the lowering distance Lc from the one-side negative electrode cutting edge 41fc of the one-side spacer edge 80fc and the lowering distance Ld from the other-side positive electrode cutting edge 31fd of the other-side spacer edge 80fd are too large, the electrode body Load unevenness occurs in the 30 flat plate portions 30h, and the capacity deterioration (decrease in capacity maintenance rate) accompanying use (charging / discharging) of the battery 10 increases. On the other hand, in the battery 10, the pull-down distance Lc from the one-side negative electrode cutting edge 41 fc of the one-side spacer edge 80 fc is within 8.0 mm, and the other-side positive electrode cutting edge of the other-side spacer edge 80 fd is The pulling distance Ld from 31 fd is within 8.0 mm. Thereby, the capacity | capacitance degradation accompanying use of the battery 10 can be suppressed appropriately.

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the implementation form, a plurality of sheets (three pieces) has shown an example of extensive spacer 80 may be a single spacer (one by one side).
Further, in the embodiment, the battery 10 in which the spacer 80 is disposed on both sides of the electrode body 30 in the electrode body thickness direction FH is illustrated, but the present invention is not limited thereto. The spacer may be disposed only on one side of the electrode body in the electrode body thickness direction FH.

DESCRIPTION OF SYMBOLS 10 Battery 20 Battery case 30 Electrode body 30c Positive electrode protruding winding part 30d Negative electrode protruding winding part 30e Central winding part 30f One side curved end part 30g The other side curved end part 30h Flat plate part 31 Positive electrode plate 31c (Axial direction of positive electrode plate Edge side 31f of positive electrode edge 31fc one side positive electrode cutting edge 31fd other side positive electrode cutting edge (positive electrode cutting edge)
41 Negative electrode plate 41d (on the other side in the axial direction of the negative electrode plate) edge portion 41f Negative electrode edge 41fc One-side negative electrode cutting edge (negative electrode cutting edge)
41fd Other side negative electrode cutting edge 51 Separator 80 Spacer 80f Spacer edge 80fc One side spacer edge 80fd Other side spacer edge 80fe Width direction first edge 80ff Width direction second edge AX Axis (winding axis)
EH Axial direction EC (Axial direction) One side ED (Axial direction) Other side MH (Positive plate) Longitudinal direction NH (Negative plate) Longitudinal direction Lc, Ld Pulling distance

Claims (1)

A belt-like positive electrode plate and a belt-like negative electrode plate are overlapped with each other via a belt-like separator and wound around in a flat shape around the axis, and the edge on one side in the axial direction along the axis of the positive electrode plate is An electrode body projecting in a flat spiral shape from the separator toward the one side, and having an end edge on the other side in the axial direction of the negative electrode plate projecting in a flat spiral shape from the separator toward the other side When,
A battery case that houses the electrode body;
A battery that is disposed between the battery case and the electrode body, and includes a plate-shaped spacer that overlaps at least a plate portion in which the positive electrode plate, the negative electrode plate, and the separator overlap in a flat plate shape. Because
The positive electrode plate is
On the other side, it has a positive electrode cutting edge generated when the positive electrode plate is formed by cutting in the longitudinal direction,
The negative electrode plate is
On the one side, having a negative electrode cutting edge generated when the negative electrode plate is formed by cutting in the longitudinal direction,
The spacer is
It is made of resin, and among the spacer edges, one side spacer edge located on the one side is 4.0 to 8.0 mm from the negative electrode cutting edge and located on the other side, and the other side The battery is formed by arranging the other-side spacer edge located on the one side of 4.0 to 8.0 mm from the positive electrode cutting edge.

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